We are developing a service to manage automation workflows around a gate using Milestone LPR. I am wondering if the SDK has a way of sending events when LPR cameras pickup a license plate and can pass the plate number in the event object?

Yes, we have and please see this sample -

https://doc.developer.milestonesys.com/html/index.html?base=samples/alarmviewer_sample.html&tree=tree_2.html

You will see LPR events in the sample. Please explore, it might be helpful for you.